On July 21, scouts, summer campers and Ecoteens had a chance to get their most pressing climate questions answered from Ian Joughin, the leader of the Greenland Glacier Expedition that Chris has been writing about here through a live satellite link to the campsite in Greenland; later that night, adults got their turn. You can listen in, below.

The team is now back from the Greenland; here’s Chris’ last post on what they learned.

North Lake and the Journey Home

It has been a whirlwind since my last post—a hectic final week on the Greenland ice sheet studying two glacial lakes, a helicopter transfer back to the town of Ilulissat, and a long series of flights taking us home. Warm socks and down jackets are now a thing of the past—I’m typing this dispatch in 87-degree heat in Seattle (I know that’s not really hot for Texans, but it’s quite a tough adjustment for me after a month of subfreezing temperatures!)

Our final week on the ice was dedicated to exploring two nearby lakes, one of which had recently drained (dubbed “North Lake”) and another that was partially full of water when we arrived (dubbed “North North Lake”).

North Lake made the news earlier this year when Dr. Sarah Das (Woods Hole Oceanographic Institution) and Dr. Ian Joughin (University of Washington Applied Physics Lab/Polar Science Center) published a pair of papers in the journal Science about the spectacular draining event that they captured with their instrumentation in July 2006. That summer, a giant hole called a moulin opened up in the lake bed and drained the entire water volume (which is a lot; this lake is several kilometers long!) in an hour and a half. This year, the lake was already empty when we arrived (in fact, we had already heard from colleagues that it drained on July 10, the day we arrived at South Lake camp), so the research team had the freedom to explore the empty lake basin on foot.

Our visits to the North Lake basin revealed a bizarre landscape of car-sized blocks, canyons, rivers and waterfalls. The variation in the landscape on the ice sheet, particularly in the drained lake beds, is staggering. I expected it to be, well, flat, and white.

What we saw was quite different—towering blocks of pushed-up ice, rivers of freezing melt water carving their way through 60-foot deep canyons, gaping bottomless cracks and holes. The color of the ice ranges from opaque white to clear to bluebird blue. To my glaciologist companions, the landscape was also an open book. The blocks indicate where major cracks occurred (the blocks are pieces of the ice sheet that are broken loose during the cracking), and the rivers lead us to the crevasses (cracks) or holes (moulins) where the water was still pouring through the ice sheet to the bedrock. If you put your ear to the cracks, you can hear the water echoing in the depths.

It will still be some time before the final picture of the 2008 lake draining can be told. The scientists had only a brief amount of time to examine their instruments and prepare them for another year of data collecting before we had to pack up and fly out. In the coming months, scientists will be examining the data their instruments collected over the previous year. Dr. Mark Behn, a scientist from the Woods Hole Oceanographic Institution’s Geology and Geophysics department (and resident “icequakes” expert), had this comment about the data he did look at:

“Even with a 10 minute look, I can see that the quality of the data is good, which tells me the instruments are working. We can also see the timing of large cracking events that drain the lakes, which stand out as dramatic spikes on the record.”

Thank you to everyone who came in to the museum on July 21 to talk with moderator Twila Moon and Dr. Ian Joughin live from the ice. Stay tuned for future Live from the Poles expeditions on the Polar Discovery website. Until then, best wishes and thanks again for reading,